What are travaux préparatoires?
See Vienna Convention on the Law of Treaties, arts. 31-32, May 23, 1969, 1155 U.N.T.S. 331, 8 I.L.M. 679.
Travaux préparatoires, also referred to as "negotiating history" and "drafting history," are the preparatory works from the drafting and the negotiation of the treaty, and might include documents, reports, minutes, drafts, and other materials. A state party's materials on the drafting, negotiation and domestic ratification, adoption and/or implementation of a treaty might also be relevant to your research. All of these are the primary sources, or "raw materials," for researching the history of a treaty.
Finding travaux préparatoires and commentaries
As with all legal research, start by looking for secondary sources that will point you to the primary materials. For some treaties, books, articles or IGO websites and databases may provide an article-by-article guide to the history and/or application of the treaty, with expert or scholarly analysis on that article and citations to and possibly texts of the relevant travaux préparatoires. Collections of some or all of the travaux préparatoires have been published for some treaties (see examples in the next box).
To search library catalogs and article finders for books and articles, do keyword searches using some combination of (1) the treaty title or words from the treaty title, (2) words from the treaty subject and (3) words such as travaux préparatoires, commentary, guide, documents, documentary, history, negotiation, analysis, and final record. You should also do a subject search for the name of the treaty.
If you do not find a commentary on your treaty or a collection of or guide to the travaux préparatoires, you can try searching for relevant materials yourself. For example, if a convention was negotiated by a conference of nations under the auspices of the United Nations, then search in U.N. documents. See International Organizations.
For national materials on the drafting, negotiation and domestic ratification/adoption of a treaty, you will need to search sources for that country, e.g., U.S. Senate Treaty documents or other congressional publications; national yearbooks of international law and other sources of state practice. See also Foreign Law by Jurisdiction and U.S. ratification & implementation of treaties; Presidential statements, proclamations, etc.
UPDATE: À la Recherche des Travaux Préparatoires: An Approach to Researching the Drafting History of International Agreements,Globalex, by Jonathan Pratter, lists sources for selected treaties, as well as methodology for looking for travaux préparatoires.
See also specific subject tabs, e.g. Human Rights.
The next box lists examples of commentaries and collected travaux préparatoires.